Cartridge

Abstract

A cartridge includes; a first gear rotatably provided at the casing; a second gear including a toothed portion and a toothless portion; and a storing portion configured to store the second gear. The second gear includes an arm that is flexible and extends substantially along a peripheral direction of the second gear. An inner peripheral surface of the storing portion includes a bulging portion that bulges inward in a radial direction. The bulging portion has a peak portion closest to a rotation center of the second gear. The arm is deflected while the arm contacts the bulging portion. The deflection of the arm is changed from an increasing tendency to a decreasing tendency at the peak portion as a base point. The toothed portion of the second gear is separated from the first gear when the end portion of the arm has crossed over the peak portion.

1. A cartridge comprising:
 a casing; 
 a first gear rotatably provided at the casing; 
 a second gear including a toothed portion and a toothless portion, the toothed portion being provided on a part of an outer periphery of the second gear and configured to mesh with the first gear, and the toothless portion being provided on a remaining part of the outer periphery of the second gear and configured to be free from meshing with the first gear; and 
 a storing portion formed at the casing and configured to store the second gear, the storing portion including an inner peripheral surface that faces the second gear, 
 wherein the second gear comprises an arm that is flexible and extends substantially along a peripheral direction of the second gear, 
 wherein the inner peripheral surface includes a bulging portion that bulges inward in a radial direction of the second gear and is allowed to contact an end portion of the arm, 
 wherein the bulging portion has a peak portion that is closest to a rotation center of the second gear, 
 wherein the arm moves in association with a rotation of the second gear in one direction and is deflected while the arm contacts the bulging portion, 
 wherein a change tendency of deflection amounts of the arm is changed from an increasing tendency to a decreasing tendency at the peak portion as a base point, and 
 wherein the toothed portion of the second gear is separated from the first gear when the end portion of the arm has crossed over the peak portion of the bulging portion in the one direction. 
 
     
     
       2. The cartridge according to  claim 1 , wherein the arm extends substantially in the one direction. 
     
     
       3. The cartridge according to  claim 1 , wherein the inner peripheral surface of the storing portion includes an engagement recess portion provided at a downstream side in the one direction of the bulging portion and configured to engage with the end portion of the arm. 
     
     
       4. The cartridge according to  claim 1 ,
 wherein the inner peripheral surface of the storing portion includes an area which opposes the end portion of the arm when the second gear is situated at an initial position, and 
 wherein the area is displaced outward in the radial direction such that the area is spaced from the end portion of the arm in a non-deformed state. 
 
     
     
       5. The cartridge according to  claim 1 ,
 wherein the second gear includes a projection portion projecting outward in the radial direction of the second gear; and 
 wherein the casing includes a regulation portion provided outside the storing portion and configured to engage with the projection portion when or after the gear tooth portion of the second gear is separated from the first gear, thereby regulating a rotation of the second gear in the one direction. 
 
     
     
       6. The cartridge according to  claim 1 , wherein the bulging portion includes a flat portion containing the peak portion, the flat portion extends orthogonal to the radial direction of the second gear. 
     
     
       7. The cartridge according to  claim 1 ,
 wherein the inner peripheral surface of the storing portion includes an area which opposes the end portion of the arm during a rotation of the second gear from an initial position in the one direction, the area of the inner peripheral surface including: a large-diameter surface portion, an intermediate-diameter surface portion, a plane surface portion, an inclined surface portion, a distantly-separated surface portion and a longitudinal wall surface portion, which are continuously provided in this order in the one direction, 
 wherein the large-diameter surface portion has a diameter greater than a distance from a center of the second gear to the end portion of the arm in a non-deformed state; 
 wherein the intermediate-diameter surface portion has a smaller diameter than the large-diameter surface portion; 
 wherein, on the plane surface portion, a distance between the plane surface portion and the center of the gear gradually decreases toward the one direction from a boundary with the intermediate-diameter surface portion and gradually increases with respect to the one direction from a predetermined position at the plane surface portion; 
 wherein the inclined surface portion is tilted outward in the radial direction toward the one direction from the plane surface portion; 
 wherein the distantly-separated surface portion is distant from a center of the second gear than from the plane surface portion, and 
 wherein the longitudinal wall surface portion extends toward the center of the second gear.